Configuring MPLS fast reroute using one-to-one backup

To configure MPLS fast reroute by using the one-to-one backup method for a defined LSP, complete the following steps.

Enable the device for configuration.
```
device# configure
```
Enable the MPLS router.
```
device(config)# router mpls 
```
Configure the LSP.
```
device(config-router-mpls)# lsp frr_tunnel
```
In this example, the specified LSPs name is frr_tunnel.
Configure the egress router of the LSP.
```
device(config-router-mpls-lsp-frr_tunnel)# to 10.1.1.1
```
In this example, the egress router IP address of the LSP is 10.1.1.1.
Configure the primary path.
```
device(config-router-mpls-lsp-frr_tunnel)# primary-path direct_path
```
In this example, the primary paths name is direct_path.
Configure the secondary path.
```
device(config-router-mpls-lsp-frr_tunnel)# secondary-path alt_path
```
In this example, the secondary paths name is alt_path.

Enable configuration of fast reroute options.

device(config-router-mpls-lsp-frr_tunnel)# frr

Configure bandwidth for the backup LSP.
```
device(config-router-mpls-lsp-frr-tunnel_frr)# bandwidth 100
```
In this example, the bandwidth is configured to 100 kbits/sec.
Configure the number of hops the backup LSP can traverse (from PLR to MP).
```
device(config-router-mpls-lsp-frr-tunnel_frr)# hop-limit 20
```
In this example, the hop limit is configure a maximum of 20.

In the following example, MPLS Fast Reroute is configured by using the one-to-one backup method for a defined LSP named frr_tunnel .

device# configure 
device(config)# router mpls
device(config-router-mpls)# lsp frr_tunnel
device(config-router-mpls-lsp-frr_tunnel)# to 10.1.1.1
device(config-router-mpls-lsp-frr_tunnel)# primary-path direct_path
device(config-router-mpls-lsp-frr_tunnel)# secondary-path alt_path
device(config-router-mpls-lsp-frr_tunnel)# frr
device(config-router-mpls-lsp-frr_tunnel-frr)# bandwidth 100
device(config-router-mpls-lsp-frr_tunnel-frr)# hop-limit 20

Th frr command enables MPLS Fast Reroute using the one-to-one backup on the LSP under whose configuration it is enabled.